There are several devices on the market today which are designed for the early detection of deep vein thrombosis. The devices include hand-held detector probes sensitive to radiation, and electronics to convert the detected radiation to meaningful data. Typically, such devices are operated in the leg region.
In this procedure, an I-125 labeled fibrinogen is intravenously injected into the patent. Then, the leg is marked with a map to guide the operator in sequentially positioning the detector probe. Once the injected fibrinogen tracer has dispersed throughout the body (in the neighborhood of three hours), radiation readings are taken with the deep vein thrombosis detection apparatus. First, a precordial count is made, and the, with the markings previously positioned on the leg, radiation counts are made along the leg, generally as a percent of the precordial count, and the readings are plotted. Localized excesses of the radioactive fibrinogen tracer are indicative of dot formations.
While the procedures for detecting deep vein thrombosis have proven valuable, sensitivity is lost because of the relatively crude techniques employed for positioning the detector probe on the area of interest. That is, by drawing spaced-apart lines on the leg, and then positioning the probe between successive lines during a counting and plotting operation, areas of the leg between markings are not scanned. This is basically because the outside diameter of the detector probe is greater than the effective diameter of the detector crystal itself.
It is toward increasing the sensitivity of deep vein thrombosis detection that the present invention is directed.